This is admittedly a variation on why study Latin (see Related questions below), but there is specific aspect/motivation that I would like to explore deeper.
Often cited reasons for studying classical languages (like Latin, Ancient Greek, Biblical Hebrew, Sanskrit, Classical Arabic) are:
- Religious reasons
- Their cultural importance
- Their closeness to one's native language
Other reason cited are intellectual curiosity and even that mastering Latin (or another dead language) first would make it easier to learn other languages. Until recently this has not seemed to me as a serious claim, due to my personal experience of learning several foreign languages - the amount of effort and time required for learning a language to a decent level is simply too prohibitive, to learn two languages instead of one target language.
There is however another way to look at it: Classical language manuals seem to attack head on the mechanics of the target language (phonetic laws, sentence structure, etc.), whereas the manuals for learning living languages understandably focus firstly on colloquial and everyday matters, leaving understanding of fine points to advanced learner (if one ever become one, as by then one has working knowledge of the language.)
The narrower question is thus: does learning a classical language help to improve one's mastery of other languages (and how much beyond word etymology)?
- Studying modern languages necessarily addresses the ensemble of the major language skills: listening/speaking, reading/writing, and understanding language structures (these are the five addressed in the tests designed according to CEFR framework.) In studying classical languages one likely focuses mainly on reading and understanding language structures.
- Modern languages require being able to "perform in real time", which poses stringent demands on pronunciation and vocabulary knowledge, whereas working on a text in a classical language can be done with a dictionary and at a slower pace.
- Working on a written text likely requires deeper understanding/knowledge of advanced syntactic structures, whereas for live languages the priority is correctly building simple phrases. The compound/complex sentences are usually left to advanced courses.